/**
 * Copyright (c) 2012-2013, Michael Yang 杨福海 (www.yangfuhai.com). Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under the License.
 */
package org.afinal.simplecache;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

import org.json.JSONArray;
import org.json.JSONObject;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

/**
 * @author Michael Yang（www.yangfuhai.com） update at 2013.08.07
 */
public class ACache {

    public static final int TIME_HOUR=60 * 60;

    public static final int TIME_DAY=TIME_HOUR * 24;

    private static final int MAX_SIZE=1000 * 1000 * 50; // 50 mb

    private static final int MAX_COUNT=Integer.MAX_VALUE; // 不限制存放数据的数量

    private static final String TAG="ACache";

    private static Map<String, ACache> mInstanceMap=new HashMap<String, ACache>();

    private ACacheManager mCache;

    public static ACache get(Context ctx) {
        return get(ctx, "ACache");
    }

    public static ACache get(Context ctx, String cacheName) {
        File f=new File(ctx.getFilesDir(), cacheName);
        return get(f, MAX_SIZE, MAX_COUNT);
    }

    public static ACache get(File cacheDir) {
        return get(cacheDir, MAX_SIZE, MAX_COUNT);
    }

    public static ACache get(Context ctx, long max_zise, int max_count) {
        File f=new File(ctx.getFilesDir(), "ACache");
        return get(f, max_zise, max_count);
    }

    public static ACache get(File cacheDir, long max_zise, int max_count) {
        ACache manager=mInstanceMap.get(cacheDir.getAbsoluteFile() + myPid());
        if(manager == null) {
            manager=new ACache(cacheDir, max_zise, max_count);
            mInstanceMap.put(cacheDir.getAbsolutePath() + myPid(), manager);
        }
        return manager;
    }

    private static String myPid() {
        return "_" + android.os.Process.myPid();
    }

    private ACache(File cacheDir, long max_size, int max_count) {
        if(!cacheDir.exists() && !cacheDir.mkdirs()) {
            throw new RuntimeException("can't make dirs in " + cacheDir.getAbsolutePath());
        }
        mCache=new ACacheManager(cacheDir, max_size, max_count);
    }

    /**
     * Provides a means to save a cached file before the data are available. Since writing about the file is complete, and its close
     * method is called, its contents will be registered in the cache. Example of use: ACache cache = new ACache(this) try {
     * OutputStream stream = cache.put("myFileName") stream.write("some bytes".getBytes()); // now update cache! stream.close(); }
     * catch(FileNotFoundException e){ e.printStackTrace() }
     */
    class xFileOutputStream extends FileOutputStream {

        File file;

        public xFileOutputStream(File file) throws FileNotFoundException {
            super(file);
            this.file=file;
        }

        public void close() throws IOException {
            super.close();
            mCache.put(file);
        }
    }

    // =======================================
    // ============ String数据 读写 ==============
    // =======================================
    /**
     * 保存 String数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的String数据
     */
    public void put(String key, String value) {
        File file=mCache.newFile(key);
        BufferedWriter out=null;
        try {
            out=new BufferedWriter(new FileWriter(file), 1024);
            out.write(value);
        } catch(IOException e) {
            e.printStackTrace();
        } finally {
            if(out != null) {
                try {
                    out.flush();
                    out.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
            mCache.put(file);
        }
    }

    /**
     * 保存 String数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的String数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, String value, int saveTime) {
        put(key, Utils.newStringWithDateInfo(saveTime, value));
    }

    /**
     * 读取 String数据
     * @param key
     * @return String 数据
     */
    public String getAsString(String key) {
        File file=mCache.get(key);
        if(!file.exists())
            return null;
        boolean removeFile=false;
        BufferedReader in=null;
        try {
            in=new BufferedReader(new FileReader(file));
            String readString="";
            String currentLine;
            while((currentLine=in.readLine()) != null) {
                readString+=currentLine;
            }
            if(!Utils.isDue(readString)) {
                return Utils.clearDateInfo(readString);
            } else {
                removeFile=true;
                return null;
            }
        } catch(IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            if(in != null) {
                try {
                    in.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
            if(removeFile)
                remove(key);
        }
    }

    // =======================================
    // ============= JSONObject 数据 读写 ==============
    // =======================================
    /**
     * 保存 JSONObject数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的JSON数据
     */
    public void put(String key, JSONObject value) {
        put(key, value.toString());
    }

    /**
     * 保存 JSONObject数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的JSONObject数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, JSONObject value, int saveTime) {
        put(key, value.toString(), saveTime);
    }

    /**
     * 读取JSONObject数据
     * @param key
     * @return JSONObject数据
     */
    public JSONObject getAsJSONObject(String key) {
        String JSONString=getAsString(key);
        try {
            JSONObject obj=new JSONObject(JSONString);
            return obj;
        } catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    // =======================================
    // ============ JSONArray 数据 读写 =============
    // =======================================
    /**
     * 保存 JSONArray数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的JSONArray数据
     */
    public void put(String key, JSONArray value) {
        put(key, value.toString());
    }

    /**
     * 保存 JSONArray数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的JSONArray数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, JSONArray value, int saveTime) {
        put(key, value.toString(), saveTime);
    }

    /**
     * 读取JSONArray数据
     * @param key
     * @return JSONArray数据
     */
    public JSONArray getAsJSONArray(String key) {
        String JSONString=getAsString(key);
        try {
            JSONArray obj=new JSONArray(JSONString);
            return obj;
        } catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    // =======================================
    // ============== byte 数据 读写 =============
    // =======================================
    /**
     * 保存 byte数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的数据
     */
    public void put(String key, byte[] value) {
        File file=mCache.newFile(key);
        FileOutputStream out=null;
        try {
            out=new FileOutputStream(file);
            out.write(value);
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            if(out != null) {
                try {
                    out.flush();
                    out.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
            mCache.put(file);
        }
    }

    /**
     * Cache for a stream
     * @param key the file name.
     * @return OutputStream stream for writing data.
     * @throws FileNotFoundException if the file can not be created.
     */
    public OutputStream put(String key) throws FileNotFoundException {
        return new xFileOutputStream(mCache.newFile(key));
    }

    /**
     * @param key the file name.
     * @return (InputStream or null) stream previously saved in cache.
     * @throws FileNotFoundException if the file can not be opened
     */
    public InputStream get(String key) throws FileNotFoundException {
        File file=mCache.get(key);
        if(!file.exists())
            return null;
        return new FileInputStream(file);
    }

    /**
     * 保存 byte数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, byte[] value, int saveTime) {
        put(key, Utils.newByteArrayWithDateInfo(saveTime, value));
    }

    /**
     * 获取 byte 数据
     * @param key
     * @return byte 数据
     */
    public byte[] getAsBinary(String key) {
        RandomAccessFile RAFile=null;
        boolean removeFile=false;
        try {
            File file=mCache.get(key);
            // LogUtil.i(TAG, "file:"+file);
            if(!file.exists())
                return null;
            RAFile=new RandomAccessFile(file, "r");
            byte[] byteArray=new byte[(int)RAFile.length()];
            RAFile.read(byteArray);
            if(!Utils.isDue(byteArray)) {
                return Utils.clearDateInfo(byteArray);
            } else {
                removeFile=true;
                return null;
            }
        } catch(Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            if(RAFile != null) {
                try {
                    RAFile.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
            if(removeFile)
                remove(key);
        }
    }

    // =======================================
    // ============= 序列化 数据 读写 ===============
    // =======================================
    /**
     * 保存 Serializable数据 到 缓存中
     * @param key 保存的key
     * @param value 保存的value
     */
    public void put(String key, Serializable value) {
        // LogUtil.i(TAG, "value:"+value);
        put(key, value, -1);
    }

    /**
     * 保存 Serializable数据到 缓存中
     * @param key 保存的key
     * @param value 保存的value
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, Serializable value, int saveTime) {
        ByteArrayOutputStream baos=null;
        ObjectOutputStream oos=null;
        try {
            baos=new ByteArrayOutputStream();
            oos=new ObjectOutputStream(baos);
            oos.writeObject(value);
            byte[] data=baos.toByteArray();
            if(saveTime != -1) {
                put(key, data, saveTime);
            } else {
                put(key, data);
            }
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            try {
                oos.close();
            } catch(IOException e) {
            }
        }
    }

    /**
     * 读取 Serializable数据
     * @param key
     * @return Serializable 数据
     */
    public Object getAsObject(String key) {
        byte[] data=getAsBinary(key);
        // LogUtil.i(TAG, "data:"+data);
        if(data != null) {
            ByteArrayInputStream bais=null;
            ObjectInputStream ois=null;
            try {
                bais=new ByteArrayInputStream(data);
                ois=new ObjectInputStream(bais);
                Object reObject=ois.readObject();
                return reObject;
            } catch(Exception e) {
                e.printStackTrace();
                return null;
            } finally {
                try {
                    if(bais != null)
                        bais.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
                try {
                    if(ois != null)
                        ois.close();
                } catch(IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;

    }

    // =======================================
    // ============== bitmap 数据 读写 =============
    // =======================================
    /**
     * 保存 bitmap 到 缓存中
     * @param key 保存的key
     * @param value 保存的bitmap数据
     */
    public void put(String key, Bitmap value) {
        put(key, Utils.Bitmap2Bytes(value));
    }

    /**
     * 保存 bitmap 到 缓存中
     * @param key 保存的key
     * @param value 保存的 bitmap 数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, Bitmap value, int saveTime) {
        put(key, Utils.Bitmap2Bytes(value), saveTime);
    }

    /**
     * 读取 bitmap 数据
     * @param key
     * @return bitmap 数据
     */
    public Bitmap getAsBitmap(String key) {
        if(getAsBinary(key) == null) {
            return null;
        }
        return Utils.Bytes2Bimap(getAsBinary(key));
    }

    // =======================================
    // ============= drawable 数据 读写 =============
    // =======================================
    /**
     * 保存 drawable 到 缓存中
     * @param key 保存的key
     * @param value 保存的drawable数据
     */
    public void put(String key, Drawable value) {
        put(key, Utils.drawable2Bitmap(value));
    }

    /**
     * 保存 drawable 到 缓存中
     * @param key 保存的key
     * @param value 保存的 drawable 数据
     * @param saveTime 保存的时间，单位：秒
     */
    public void put(String key, Drawable value, int saveTime) {
        put(key, Utils.drawable2Bitmap(value), saveTime);
    }

    /**
     * 读取 Drawable 数据
     * @param key
     * @return Drawable 数据
     */
    public Drawable getAsDrawable(String key) {
        if(getAsBinary(key) == null) {
            return null;
        }
        return Utils.bitmap2Drawable(Utils.Bytes2Bimap(getAsBinary(key)));
    }

    /**
     * 获取缓存文件
     * @param key
     * @return value 缓存的文件
     */
    public File file(String key) {
        File f=mCache.newFile(key);
        if(f.exists())
            return f;
        return null;
    }

    /**
     * 移除某个key
     * @param key
     * @return 是否移除成功
     */
    public boolean remove(String key) {
        return mCache.remove(key);
    }

    /**
     * 清除所有数据
     */
    public void clear() {
        mCache.clear();
    }

    /**
     * @title 缓存管理器
     * @author 杨福海（michael） www.yangfuhai.com
     * @version 1.0
     */
    public class ACacheManager {

        private final AtomicLong cacheSize;

        private final AtomicInteger cacheCount;

        private final long sizeLimit;

        private final int countLimit;

        private final Map<File, Long> lastUsageDates=Collections.synchronizedMap(new HashMap<File, Long>());

        protected File cacheDir;

        private ACacheManager(File cacheDir, long sizeLimit, int countLimit) {
            this.cacheDir=cacheDir;
            this.sizeLimit=sizeLimit;
            this.countLimit=countLimit;
            cacheSize=new AtomicLong();
            cacheCount=new AtomicInteger();
            calculateCacheSizeAndCacheCount();
        }

        /**
         * 计算 cacheSize和cacheCount
         */
        private void calculateCacheSizeAndCacheCount() {
            new Thread(new Runnable() {

                @Override
                public void run() {
                    int size=0;
                    int count=0;
                    File[] cachedFiles=cacheDir.listFiles();
                    if(cachedFiles != null) {
                        for(File cachedFile: cachedFiles) {
                            size+=calculateSize(cachedFile);
                            count+=1;
                            lastUsageDates.put(cachedFile, cachedFile.lastModified());
                        }
                        cacheSize.set(size);
                        cacheCount.set(count);
                    }
                }
            }).start();
        }

        private void put(File file) {
            int curCacheCount=cacheCount.get();
            while(curCacheCount + 1 > countLimit) {
                long freedSize=removeNext();
                cacheSize.addAndGet(-freedSize);

                curCacheCount=cacheCount.addAndGet(-1);
            }
            cacheCount.addAndGet(1);

            long valueSize=calculateSize(file);
            long curCacheSize=cacheSize.get();
            while(curCacheSize + valueSize > sizeLimit) {
                long freedSize=removeNext();
                curCacheSize=cacheSize.addAndGet(-freedSize);
            }
            cacheSize.addAndGet(valueSize);

            Long currentTime=System.currentTimeMillis();
            file.setLastModified(currentTime);
            lastUsageDates.put(file, currentTime);
        }

        private File get(String key) {
            File file=newFile(key);
            Long currentTime=System.currentTimeMillis();
            file.setLastModified(currentTime);
            lastUsageDates.put(file, currentTime);

            return file;
        }

        private File newFile(String key) {
            return new File(cacheDir, key.hashCode() + "");
        }

        private boolean remove(String key) {
            File image=get(key);
            return image.delete();
        }

        private void clear() {
            lastUsageDates.clear();
            cacheSize.set(0);
            File[] files=cacheDir.listFiles();
            if(files != null) {
                for(File f: files) {
                    f.delete();
                }
            }
        }

        /**
         * 移除旧的文件
         * @return
         */
        private long removeNext() {
            if(lastUsageDates.isEmpty()) {
                return 0;
            }

            Long oldestUsage=null;
            File mostLongUsedFile=null;
            Set<Entry<File, Long>> entries=lastUsageDates.entrySet();
            synchronized(lastUsageDates) {
                for(Entry<File, Long> entry: entries) {
                    if(mostLongUsedFile == null) {
                        mostLongUsedFile=entry.getKey();
                        oldestUsage=entry.getValue();
                    } else {
                        Long lastValueUsage=entry.getValue();
                        if(lastValueUsage < oldestUsage) {
                            oldestUsage=lastValueUsage;
                            mostLongUsedFile=entry.getKey();
                        }
                    }
                }
            }

            long fileSize=calculateSize(mostLongUsedFile);
            if(mostLongUsedFile.delete()) {
                lastUsageDates.remove(mostLongUsedFile);
            }
            return fileSize;
        }

        private long calculateSize(File file) {
            return file.length();
        }
    }

    /**
     * @title 时间计算工具类
     * @author 杨福海（michael） www.yangfuhai.com
     * @version 1.0
     */
    private static class Utils {

        /**
         * 判断缓存的String数据是否到期
         * @param str
         * @return true：到期了 false：还没有到期
         */
        private static boolean isDue(String str) {
            return isDue(str.getBytes());
        }

        /**
         * 判断缓存的byte数据是否到期
         * @param data
         * @return true：到期了 false：还没有到期
         */
        private static boolean isDue(byte[] data) {
            String[] strs=getDateInfoFromDate(data);
            if(strs != null && strs.length == 2) {
                String saveTimeStr=strs[0];
                while(saveTimeStr.startsWith("0")) {
                    saveTimeStr=saveTimeStr.substring(1, saveTimeStr.length());
                }
                long saveTime=Long.valueOf(saveTimeStr);
                long deleteAfter=Long.valueOf(strs[1]);
                if(System.currentTimeMillis() > saveTime + deleteAfter * 1000) {
                    return true;
                }
            }
            return false;
        }

        private static String newStringWithDateInfo(int second, String strInfo) {
            return createDateInfo(second) + strInfo;
        }

        private static byte[] newByteArrayWithDateInfo(int second, byte[] data2) {
            byte[] data1=createDateInfo(second).getBytes();
            byte[] retdata=new byte[data1.length + data2.length];
            System.arraycopy(data1, 0, retdata, 0, data1.length);
            System.arraycopy(data2, 0, retdata, data1.length, data2.length);
            return retdata;
        }

        private static String clearDateInfo(String strInfo) {
            if(strInfo != null && hasDateInfo(strInfo.getBytes())) {
                strInfo=strInfo.substring(strInfo.indexOf(mSeparator) + 1, strInfo.length());
            }
            return strInfo;
        }

        private static byte[] clearDateInfo(byte[] data) {
            if(hasDateInfo(data)) {
                return copyOfRange(data, indexOf(data, mSeparator) + 1, data.length);
            }
            return data;
        }

        private static boolean hasDateInfo(byte[] data) {
            return data != null && data.length > 15 && data[13] == '-' && indexOf(data, mSeparator) > 14;
        }

        private static String[] getDateInfoFromDate(byte[] data) {
            if(hasDateInfo(data)) {
                String saveDate=new String(copyOfRange(data, 0, 13));
                String deleteAfter=new String(copyOfRange(data, 14, indexOf(data, mSeparator)));
                return new String[]{saveDate, deleteAfter};
            }
            return null;
        }

        private static int indexOf(byte[] data, char c) {
            for(int i=0; i < data.length; i++) {
                if(data[i] == c) {
                    return i;
                }
            }
            return -1;
        }

        private static byte[] copyOfRange(byte[] original, int from, int to) {
            int newLength=to - from;
            if(newLength < 0)
                throw new IllegalArgumentException(from + " > " + to);
            byte[] copy=new byte[newLength];
            System.arraycopy(original, from, copy, 0, Math.min(original.length - from, newLength));
            return copy;
        }

        private static final char mSeparator=' ';

        private static String createDateInfo(int second) {
            String currentTime=System.currentTimeMillis() + "";
            while(currentTime.length() < 13) {
                currentTime="0" + currentTime;
            }
            return currentTime + "-" + second + mSeparator;
        }

        /*
         * Bitmap → byte[]
         */
        private static byte[] Bitmap2Bytes(Bitmap bm) {
            if(bm == null) {
                return null;
            }
            ByteArrayOutputStream baos=new ByteArrayOutputStream();
            bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
            return baos.toByteArray();
        }

        /*
         * byte[] → Bitmap
         */
        private static Bitmap Bytes2Bimap(byte[] b) {
            if(b.length == 0) {
                return null;
            }
            return BitmapFactory.decodeByteArray(b, 0, b.length);
        }

        /*
         * Drawable → Bitmap
         */
        private static Bitmap drawable2Bitmap(Drawable drawable) {
            if(drawable == null) {
                return null;
            }
            // 取 drawable 的长宽
            int w=drawable.getIntrinsicWidth();
            int h=drawable.getIntrinsicHeight();
            // 取 drawable 的颜色格式
            Bitmap.Config config=drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
            // 建立对应 bitmap
            Bitmap bitmap=Bitmap.createBitmap(w, h, config);
            // 建立对应 bitmap 的画布
            Canvas canvas=new Canvas(bitmap);
            drawable.setBounds(0, 0, w, h);
            // 把 drawable 内容画到画布中
            drawable.draw(canvas);
            return bitmap;
        }

        /*
         * Bitmap → Drawable
         */
        @SuppressWarnings("deprecation")
        private static Drawable bitmap2Drawable(Bitmap bm) {
            if(bm == null) {
                return null;
            }
            BitmapDrawable bd=new BitmapDrawable(bm);
            bd.setTargetDensity(bm.getDensity());
            return new BitmapDrawable(bm);
        }
    }

}
